Went straight to recursion, which felt right.
Clarify the definition of 'identical' (structure and node values) and then present a recursive solution that compares the roots and recursively checks left and right subtrees. Discuss iterative alternatives (e.g., using a stack or queue) and analyze time and space complexity.
Pro tip: Mention that the recursive solution can cause stack overflow for very deep trees, so an iterative approach using an explicit stack might be preferable in production systems. Also, note that early termination on mismatch makes the average case faster.
Confirm that 'identical' means both structure and node values must match exactly. Ask about edge cases like empty trees or trees with one node.
Decide between recursive and iterative solutions. Recursive is simpler and more elegant; iterative avoids stack overflow for deep trees.
For recursion: if both nodes are null, return true; if one is null, return false; if values differ, return false; otherwise recurse on left and right subtrees. For iteration: use a stack (or queue) to simulate recursion.
Time complexity is O(n) where n is the number of nodes (or min(n,m) if sizes differ). Space complexity is O(h) for recursion (h = height) or O(n) for iterative in worst case.
Walk through simple cases: both empty, one empty, same values, different values, different structures. Also consider large trees and skewed trees.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.